The Mercedes-Benz S-Class W220 S 350 represents the pinnacle of luxury and technological innovation for its time. Known for its comfort, performance, and advanced features, this model continues to be admired by enthusiasts and owners alike. However, the W220 S 350, like any vehicle, is not immune to certain recurring issues. From mechanical failures to electrical glitches, understanding the common problems of the W220 S 350 is essential for maintaining its value and functionality. This comprehensive guide will explore these issues in detail, their causes, and the most effective solutions.
Mercedes S-Class W220 S 350 Engine Performance Problems
The 3.7-liter V6 engine in the Mercedes S 350 is a reliable workhorse, but it is not without its vulnerabilities. Several common engine-related problems include oil leaks, timing chain issues, and crankshaft position sensor failures.
Oil leaks are among the most frequently reported issues in the W220 S 350. Owners often notice oil puddles under the car or detect a burning oil smell while driving. The leaks typically originate from the valve cover gaskets, oil cooler seals, or the rear main seal. The primary cause of oil leaks is the deterioration of rubber gaskets and seals due to prolonged exposure to engine heat and pressure. Poor maintenance, such as infrequent oil changes, can accelerate the degradation of these components. Addressing oil leaks requires replacing the worn gaskets and seals, a labor-intensive but necessary procedure. Regular oil changes using high-quality synthetic oil and monitoring oil levels can help prevent this issue.
Timing chain problems are another significant concern for the S 350. The timing chain is responsible for synchronizing the engine's camshaft and crankshaft, and any failure in this component can lead to severe engine damage. Over time, the timing chain can stretch, or its tensioners and guides can wear out, resulting in engine misfires, rattling noises, or a check engine light. The most common cause of timing chain issues is insufficient lubrication, often due to neglected oil changes. Solving this problem involves replacing the timing chain, tensioners, and guides. Preventative maintenance, such as adhering to recommended oil change intervals, can extend the life of these components.
The crankshaft position sensor is another component that can fail in the W220 S 350. This sensor monitors the position and speed of the crankshaft to ensure proper engine timing. When it fails, symptoms include difficulty starting the engine, stalling, or reduced performance. The failure is often caused by electrical faults or overheating. Replacing the faulty sensor is the only solution, and regular inspections can help identify early signs of sensor failure.
Mercedes S-Class W220 S 350 Transmission Issues
The automatic transmission in the Mercedes S 350 is designed for smooth and seamless gear shifts, but as the vehicle ages, certain issues may arise that affect its performance. Gear slipping, delayed shifts, and torque converter problems are some of the most common transmission complaints.
Gear slipping and delayed shifts are frequently reported by W220 owners. These issues can manifest as hesitation when accelerating or a failure to engage gears properly. The primary causes include wear and tear on the valve body, a failing conductor plate, or contaminated transmission fluid. Over time, debris and sludge can build up in the transmission, causing internal components to malfunction. Fixing these issues often requires a thorough transmission fluid flush, replacing the filter, and addressing worn components like the valve body or conductor plate.
Torque converter problems are another common issue. The torque converter transfers engine power to the transmission, enabling smooth acceleration. When it fails, drivers may experience vibrations, difficulty shifting gears, or reduced fuel efficiency. The most common cause of torque converter failure is overheating due to low or degraded transmission fluid. Replacing the faulty torque converter is essential to restore transmission function. Regular fluid changes and ensuring proper transmission cooling can prevent these problems from occurring.
Mercedes S-Class W220 S 350 Suspension and Steering Problems
The W220 S-Class features an advanced suspension system designed for maximum comfort and handling precision. However, several common issues can arise, particularly with the Airmatic suspension system and steering components.
The Airmatic suspension system is a standout feature of the W220, offering adjustable ride height and damping. However, it is notorious for its tendency to fail. Owners often report issues such as sagging suspension, uneven ride height, or a warning light on the dashboard. The air struts are prone to leaks, and the compressor can fail due to overuse or electrical faults. Fixing these issues typically involves replacing the leaking air struts or the compressor. While OEM parts are recommended for optimal performance, aftermarket alternatives can be a more cost-effective solution. Regular inspections can catch minor leaks or compressor issues before they lead to complete suspension failure.
Steering problems, particularly with the power steering system, are also common in the W220 S 350. Many owners experience difficulty turning the steering wheel or hear whining noises when steering. These symptoms are often caused by a failing power steering pump, leaks in the hydraulic lines, or worn-out tie rods. Addressing these problems involves repairing or replacing the faulty components and ensuring the power steering fluid is at the correct level. Routine maintenance and inspections can help prevent steering issues from worsening.
Mercedes S-Class W220 S 350 Electrical System Failures
The W220 S-Class is equipped with advanced electronics, many of which were cutting-edge at the time of its release. However, these systems are complex and prone to failure as the vehicle ages. Common electrical problems include malfunctioning door locks, battery drain, and issues with the Command infotainment system.
Door lock failures are a frequent issue in the W220. Many owners report problems with the central locking system, such as doors failing to lock or unlock using the remote key fob. This problem is often caused by a faulty vacuum pump or leaks in the vacuum lines. The central locking system relies on a network of vacuum-operated components, and any disruption can compromise its functionality. Replacing the vacuum pump or repairing leaks usually resolves the issue.
Battery drain is another common electrical complaint. Owners may find their batteries drained after leaving the vehicle parked for an extended period. The drain is often caused by parasitic draws from malfunctioning components, such as control modules or interior lighting. Diagnosing battery drain requires identifying the source of the excessive current draw. Once identified, repairing or replacing the faulty component resolves the issue. Ensuring all lights and electronics are switched off when the car is parked can help prevent battery drain.
The Command infotainment system, which controls audio, navigation, and climate settings, is another source of frustration for W220 owners. Common issues include frozen screens, unresponsive controls, or system crashes. These problems are often caused by outdated software or hardware malfunctions. Updating the software or replacing faulty hardware components can restore the system's functionality. Regular updates and proper handling of the system can minimize the likelihood of these problems.
Mercedes S-Class W220 S 350 Cooling System Problems
The cooling system in the Mercedes S-Class W220 S 350 is crucial for maintaining the engine's operating temperature and preventing overheating. However, this system is not without its challenges, particularly as the vehicle ages. Common issues include radiator leaks, thermostat failures, and water pump problems.
Radiator leaks are one of the most frequently encountered cooling system problems in the W220 S 350. Many owners notice coolant puddles under the car or experience overheating during long drives. The radiator can develop cracks or corrosion over time, often due to the use of low-quality coolant or a lack of maintenance. Contaminants in the coolant can accumulate and degrade the radiator's internal structure, while road debris can cause physical damage to the exterior. Addressing this problem requires either repairing minor cracks using sealants or replacing the radiator entirely for more severe damage. To prevent radiator issues, regular coolant flushes and the use of high-quality, manufacturer-recommended coolant are essential.
Thermostat failures are another common issue that can lead to erratic engine temperature regulation. The thermostat controls the flow of coolant between the engine and radiator, and when it malfunctions, it may become stuck in the open or closed position. A stuck-open thermostat can lead to overcooling, reducing engine efficiency, while a stuck-closed thermostat can cause overheating, which can damage engine components. Replacing the thermostat is the only solution to this problem. Regular inspections of the cooling system and timely replacement of aging components can prevent thermostat failures.
Water pump problems are also a concern in the W220 S 350. The water pump is responsible for circulating coolant through the engine, and when it fails, the engine may overheat due to insufficient coolant flow. Symptoms of a failing water pump include coolant leaks near the pump, overheating, and a whining noise from the engine bay. Most water pump failures are caused by worn bearings or seals. Resolving this issue requires replacing the water pump, and during the process, it is advisable to inspect the surrounding components, such as the drive belt and pulleys, to ensure they are in good condition. Regular maintenance of the cooling system can help extend the life of the water pump.
Mercedes S-Class W220 S 350 Rust and Corrosion Problems
Rust and corrosion are significant concerns for the W220 S-Class, particularly in areas with harsh winters or frequent road salt usage. Despite Mercedes-Benz's efforts to improve corrosion resistance, many owners have reported premature rusting on their vehicles.
The most common areas affected by rust include the wheel arches, door sills, underbody, and trunk edges. Poor drainage design and insufficient rust-proofing during manufacturing are primary contributors to this issue. Water and debris can accumulate in these areas, accelerating the rusting process. Over time, rust not only affects the vehicle's aesthetics but can also compromise its structural integrity.
To address rust, the affected areas must be treated promptly. This involves sanding down the rusted surfaces, applying rust inhibitors, and repainting the areas to protect them from further damage. For severe cases, replacing the affected panels may be necessary. Preventing rust requires regular washing, especially during winter months, to remove road salt and other corrosive substances. Applying a rust-proofing treatment to vulnerable areas can provide additional protection.
Mercedes S-Class W220 S 350 Interior and Comfort Issues
The luxurious interior of the W220 S 350 is one of its defining features, but as the vehicle ages, certain comfort-related components may begin to fail. Two of the most commonly reported issues are malfunctioning power windows and problematic seat adjusters.
Power window failures are a frequent complaint among W220 owners. The power window mechanism relies on a regulator to move the window up and down. Over time, the regulator can wear out or break, causing the window to become stuck or fail to operate smoothly. Plastic components within the regulator are particularly prone to wear, especially with frequent use. Fixing this issue typically involves replacing the faulty regulator with a more durable aftermarket or OEM replacement. To prevent future problems, avoid forcing the windows and ensure the system is lubricated during routine maintenance.
Seat adjuster malfunctions are another common issue. The power-adjustable seats in the W220 allow drivers and passengers to find the most comfortable position, but the motors and switches that control these adjustments can fail over time. Symptoms include seats that are stuck in one position or unresponsive to adjustment commands. Electrical faults, worn-out motors, or damaged wiring are often to blame. Repairing or replacing the faulty components is necessary to restore functionality. Keeping the interior dry and avoiding excessive force when adjusting the seats can help prevent these issues.
Mercedes S-Class W220 S 350 Sensotronic Brake Control (SBC) System Failures
The Sensotronic Brake Control (SBC) system in the W220 S-Class is an advanced braking system designed to improve safety and performance. However, it is also one of the most problematic features of the vehicle. Many owners have experienced SBC system failures, which can lead to diminished braking performance or, in extreme cases, a complete loss of braking function.
The SBC system relies on a hydraulic pump and electronic controls to deliver precise braking force. Over time, the hydraulic pump can wear out, and the electronic components may develop faults. Mercedes-Benz issued recalls and extended warranties for SBC-equipped vehicles, so it is worth checking if your vehicle is eligible for a free repair or replacement. If not, replacing the SBC pump or control unit is the only solution. Regular brake inspections and keeping the system updated with the latest software can help extend its lifespan and ensure reliable performance.
Conclusion
The Mercedes S-Class W220 S 350 is a luxurious and technologically advanced vehicle that remains a favorite among enthusiasts. However, it is not without its challenges. From engine and transmission issues to suspension, electrical, and interior problems, understanding these common faults can help owners take proactive measures to maintain their vehicles and avoid costly repairs. Regular maintenance, prompt repairs, and attention to detail are essential to preserving the performance and longevity of this iconic model.
For expert assistance in diagnosing and repairing any issues with your Mercedes S-Class W220 S 350, visit European Auto Pro, 253 Goodwood Road, Kings Park, 5034 South Australia. Their skilled technicians specialize in Mercedes-Benz vehicles and are dedicated to keeping your car in top condition for years to come.